How can I add custom .zwo files?

You can map the zwift Workout folder using the environment variable ZWIFT_WORKOUT_DIR, for example if your workout directory is in $HOME/zwift_workouts then you would provide the environment variable ZWIFT_WORKOUT_DIR="$HOME/zwift_workouts".

You can add this variable into $HOME/.config/zwift/config or $HOME/.config/zwift/$USER-config.

The workouts folder will contain subdirectories e.g. $HOME/.config/zwift/workouts/393938. The number is your internal zwift id and you store you zwo files in the relevant folder. There will usually be only one ID, however if you have multiple zwift logins it may show one subdirectory for each, to find the ID you can use the following link:

Webpage for finding internal ID: https://www.virtualonlinecycling.com/p/zwiftid.html

Any workouts created already will be copied into this folder on first start

To add a new workout just copy the zwo file to this directory

Deleting files from the directory will not delete them, they will be re-added when re-starting zwift, you must delete from the zwift menu